cache

type CacheUpdateHandler ¶

type CacheUpdateHandler[T any] func(T)

CacheUpdateHandler is called every time the cached value is updated if requested as an option The value provided is the ExpiringValue construct which is itself containing the value within the cache The handler must not modify the value provided

type ErrorHandler ¶

type ErrorHandler func(error)

ErrorHandler is called every time an error is returned when attempting to update the cached value

type ExpiringValue ¶

type ExpiringValue[T any] struct {
	Value     T
	ExpiresAt time.Time
}

type Fetcher ¶

type Fetcher[T any] interface {
	// Stringer interface for returning a unique identifier
	fmt.Stringer

	// Fetch returns a valid ExpiringValue
	Fetch(ctx context.Context) (*ExpiringValue[T], error)
}

type Maintainer ¶

type Maintainer[T any] struct {
	// contains filtered or unexported fields
}

Maintainer is a Refresh-Ahead Cache used to ensure that a ExpiringValue is kept valid for a given RefreshAtFunc. Any call to execute must be done under the syncLock to ensure there is no concurrent calls to the provider

func NewMaintainer[T any](fetcher Fetcher[T], refreshAtFunc RefreshAtFunc, options ...option) *Maintainer[T]

func (m *Maintainer[T]) Close()

func (m *Maintainer[T]) Get(ctx context.Context) (T, error)

func (m *Maintainer[T]) IsClosed() bool

type RefreshAtFunc ¶

type RefreshAtFunc func(notBefore time.Time, notAfter time.Time) time.Time

RefreshAtFunc returns the time.Time to re-fetch the ExpiringValue. This returned time.Time should never be in the past.

func NewPercentageRemainingRefreshAt(renewAfterPercentage float64, jitterPercentage float64) RefreshAtFunc